Date: Wed, 15 Jun 2011 16:39:26 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: "Ian FREISLICH" <ianf@clue.co.za> Cc: freebsd-current@FreeBSD.org Subject: Re: Time keeping Issues with the low-resolution TSC timecounter Message-ID: <201106151639.30308.jkim@FreeBSD.org> In-Reply-To: <E1QWvkC-0001QH-Cj@clue.co.za> References: <E1QWvkC-0001QH-Cj@clue.co.za>
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On Wednesday 15 June 2011 03:27 pm, Ian FREISLICH wrote: > > > The problem I noticed first is that it takes unusually long > > > until a key press is repeated. With the default eventtimer > > > (HPET) it seems to take about 4s, which can be slightly > > > improved by switching to i8254. > > > > > > The "error beep" seems to take longer than usual, too, > > > and the system "feels sluggish" in general. > > > > > > An effect that is easier to measure is that the system is > > > unable to properly keep the time. Again the problem is less > > > severe when using i8254 instead of HPET: > > > > [SNIP] > > > > First of all, please do not mix timecounter issues with > > eventtimer. They are not directly related. > > > > Can you please show me verbose boot messages *without* your > > patch? Does "sysctl kern.timecounter.hardware=HPET" help > > *without* touching eventtimers? > > I have the same issue with my system (Atom N270). The effect that > I see is about 29 wall clock seconds are recorded as 1 system > second. Can please you send me output from the following? sh -c 'count=10; while [ $count -gt 0 ]; do count=$((count - 1));\ sysctl kern.timecounter; sleep 1; done' > I had do something similar to the OP to make my system useable since > it doesn't seem possible to influence timecounter choice at boot > time. You can just add the following line in /etc/sysctl.conf for now: kern.timecounter.hardware=HPET Jung-uk Kim
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